FIG. 6 illustrates an example of a combustion system using a combustion controlling device for controlling the operation of a combustion device (see, for example, PTL 1). This combustion system 200 includes combustion equipment 1, a combustion controlling device 2 (2B), a fuel flow channel 3, and an air flow channel 4.
The combustion equipment 1 includes a combustion chamber 5, a main burner 6 for heating the inside of the combustion chamber 5, a pilot burner 7 for igniting the main burner 6, an ignition device (IG) 8 for igniting the pilot burner 7, a flame detector 9 for detecting the strengths of flames of the burners (the pilot burner 7 and the main burner 6), and a temperature sensor 10 for detecting the temperature in the combustion chamber 5.
The fuel flow channel 3 is a flow channel through which fuel is supplied to the combustion equipment 1 and includes a main flow channel 3a to which fuel is supplied from the outside and a first flow channel 3b and a second flow channel 3c branched from the main flow channel 3a. The first flow channel 3b is connected to the main burner 6 and the second flow channel 3c is connected to the pilot burner 7. In addition, the main flow channel 3a is provided with a gas pressure switch 15, the first flow channel 3b is provided with safety shutoff valves 11 and 12, and the second flow channel 3c is provided with safety shutoff valves 13 and 14.
One end of the air flow channel 4 is connected to a blower 16 and the other end is connected to the first flow channel 3b. Air discharged from the blower 16 is supplied to the main burner 6 together with fuel (gas) via the first flow channel 3b. In addition, the air flow channel 4 is provided with a wind pressure switch (air flow switch) 17 and a damper 18.
The combustion controlling device 2 (2B) receives a flame detection signal (signal for indicating the strengths of flames of the burners) from the flame detector 9 and a temperature detection signal from the temperature sensor 10 and outputs control signals to the safety shutoff valves 11 to 14, the ignition device 8, the blower 16, the damper 18, and the like. This controls the operation of a combustion device 19 surrounded by the dot-and-dash line in the drawing.
Depending on the type of the combustion device 19, the flame of the pilot burner 7 is extinguished after ignition of the main burner 6 or the flame of the pilot burner 7 is kept even after ignition of the main burner 6. In the former type, the flame detector 9 first detects the strength of the flame of the pilot burner 7 and then detects the strength of the flame of the main burner 6. In the latter type, the strengths of the flames of the pilot burner 7 and the main burner 6 are detected in a combined manner. Another type has only the main burner 6 without having the pilot burner 7. In this specification, the pilot burner 7 and the main burner 6 are called burners and the flame detected by the flame detector 9 is called the flames of the burners. FIG. 6 illustrates the type that keeps the flame of the pilot burner 7 even after ignition of the main burner 6 and the flame detector 9 detects the flames of the pilot burner 7 and the main burner 6 as the flames of the burners.
In addition, the combustion controlling device 2 (2B) monitors the states of the gas pressure switch 15, the wind pressure switch 17, the flame detector 9, and the like and, when detecting an abnormality, closes the safety shutoff valves 11 to 14 to interrupt the supply of the fuel to the burners.
In the combustion system 200, the operational order from the start of the combustion device 19 to normal combustion is defined as a combustion sequence. For example, as the operational order from the start of the combustion device 19 to normal combustion, the time zones of combustion sequences such as “start check”, “prepurge”, “ignition waiting”, “ignition trial”, “pilot trial”, “main trial”, and “normal combustion” are determined.
With respect to such a combustion system, PTL 2 discloses a technique for transmitting, from the combustion controlling device to a remote monitoring device operated by a maintenance person, combustion controlling information from a prescribed time before the occurrence of an abnormality to the occurrence of the abnormality as trend data of combustion control and displaying the trend data in a graph on a screen (monitoring screen) of the remote monitoring device. The maintenance person can study the control state of the operation of the combustion device at the occurrence of an alarm in detail by checking the trend data of combustion control displayed in a graph and can analyze the cause of the alarm in detail.